Composite armor plate comprising a mass of spherical ceramic balls distributed in an aluminum alloy matrix is known in the prior art. However, such prior art composite armor plate suffers from one or more serious disadvantages making it difficult to manufacture and less than entirely suitable for the purpose of defeating metal projectiles.
For example, McDougal et al U.S. Pat. No. 3,705,558 discloses a lightweight armor plate comprising a layer of ceramic balls. The ceramic balls are in contact with each other and leave small gaps for entry of molten metal. In one embodiment, the ceramic balls are encased in a stainless steel wire screen; and in another embodiment, the composite armor is manufactured by adhering nickel coated alumina spheres to an aluminum alloy plate by means of a polysulfide adhesive.
Composite armor plate as described in the McDougal et al patent is difficult to manufacture because the ceramic spheres may be damaged by thermal shock arising from molten metal contact. The ceramic spheres are also sometimes displaced during casting of molten metal into interstices between the spheres.
In order to minimize such displacement, Huet U.S. Pat. No. 4,534,266 proposes a network of interlinked metal shells to encase ceramic inserts during casting of molten metal. After the metal solidifies, the metal shells are incorporated into the composite armor.
It is a principal objective of the present invention to provide composite armor with enhanced protection against penetration by projectiles.
A related objective of the present invention is to provide a coating for ceramic bodies in composite armor that reduces damage from thermal shock during manufacture and enhances resistance of the armor to penetration by projectiles.
An additional objective of the invention is to provide a method for manufacturing the improved composite armor.
Additional objectives and advantages of the present invention will become apparent to persons skilled in the art from the following detailed description of our invention.